Mostly use a glencairn, and I like mine with a single cube. Under 101 proof i drink a 2 oz pour, over that usually switch to 1.5 oz. I have 3 different sizes of ice cubes, 0.5, 0.75, and 1.0 oz which I make with bottled water, and will vary the cube size based on profile, size of pour, and/or proof.
In restaurants or bars I order neat with a side cup of ice. Otherwise I get way to much ice in my whiskey.
It occurs to me I may have OCD :-)